Two‐Phase Flow Modeling of Direct Methanol Fuel Cell Anode Compartment

Abstract

A quasi two‐dimensional numerical model was developed to predict the two‐phase flow behavior within the anode compartment of direct methanol fuel cells (DMFCs). Different void fraction correlations were employed to examine and estimate the pressure drop, flowrate and methanol concentration variations across the fuel channels. By comparing the modeling results with experimental data, it was discovered that the calculated pressure drop values were highly dependent on the type of void fraction correlation utilized. The best experimental agreement was achieved when using the “separated” flow modeling approach with a void fraction correlation that accounted for surface tension and capillary effects. The “homogenous” flow modeling methodology on the other hand, was found to be inadequate and in all cases, underestimated the two‐phase pressure drop. The model demonstrated that the acceleration and gravitational pressure losses had the lowest and highest impact on the overall two‐phase pressure drop, respectively. The frictional pressure loss effects only started to appear at higher fuel flowrates and at elevated operating current densities. It was also revealed that increasing the cell's operating current density while maintaining the fuel flowrate, would significantly increase the overall two‐phase pressure drop with negligible impact on the net methanol concentration across the anode compartment.

A High-Performance Gas-Fed Direct Ammonia Hydroxide Exchange Membrane Fuel Cell

“…Mathematical modeling of gas-fed DAFC polarization curves and their comparison with experimental polarization curves can provide valuable insights into the sources of performance loss in gas-fed DAFCs. Several one-dimensional (1-D), 2-D, and 3-D porous electrode models have been proposed and used in the field of fuel cells to model the performance of proton exchange membrane fuel cells (PEMFCs), − hydroxide exchange membrane fuel cells (HEMFCs), , and direct methanol fuel cells (DMFCs). − However, none of these models have yet been applied to DAFCs. Even though 2-D and 3-D porous electrode models are more realistic and complex, simplified and informative 1-D models are excellent starting points for understanding DAFCs.…”

The nonisothermal two‐phase model based on mixed convection in passive μDMFC

“…The magnitude of these forces determines the growth state of the bubble, and the process of detachment of the bubble. 20 In terms of the overall mass transfer of the DMFC, a quasi-twodimensional numerical model was established by Kablou et al 21 to predict the two-phase flow behavior of the DMFC anode, and the pressure drop, flow rate, and methanol concentration changes in the fuel channel under different porosities were analyzed. Turkmen et al 22 investigated the relationship between the channel pressure drop caused by methanol flow and the geometry of the flow channel on the anode side of the DMFC.…”